Study Finds Portions Of A1A In St. Johns County Could Be Vulnerable To Storm Erosion

Mar 1, 2019

A study commissioned by the Florida Department of Transportation finds that several parts of A1A in St. Johns County could be vulnerable to erosion, primarily during extreme weather events like Hurricanes Irma and Matthew.

The study, conducted by the geoscience and engineering consulting firm INTERA Incorporated, was commissioned by FDOT in response to significant storms in the last several years to evaluate and identify areas where pavement or shoulder loss would be possible during a coastal storm event.

The study focused on a 7.5 mile stretch of SR A1A from near Guana River Rd. south to the Vilano Bridge. It found that 16 percent of the clear zone or roadway is highly vulnerable to erosion, 39 percent is at medium risk and 45 percent has low vulnerability.

Clear zone refers to the unobstructed, walkable roadside area that allows a driver to stop safely or regain control of a vehicle that has left the roadway.

Ten years into the future those numbers will shift to 42 percent high vulnerability, 34 percent medium vulnerability and 24 percent low vulnerability.

Vulnerability of clear zone/roadway to erosion.
Credit INTERA incorporated

“We do not want to be in the position where Flagler County was after Matthew,” said Neal Shinkre, Public Works Director for St. Johns County.

“A1A houses about 6,000 residents on that island and that is a big economic driver for us,” said Shinkre, referring to the 7.5 mile stretch the study examined.

If portions of A1A were to be destroyed in a future storm, as it was in Flagler County during Hurricane Matthew in 2016, Shinkre said residents could be stranded on the wrong side of the intracoastal waterway.

Related: Hurricane Matthew Took A Big Bite Out Of Southeastern States’ Beaches

Longterm, that kind of damage would have a significant impact on tourism, which Shinkre said is essential to the county’s economy.

At the conclusion of the study, INTERA recommended that FDOT protect three sections of A1A by building seawalls and/or contributing to ongoing dune restoration projects.

“FDOT’s Five-Year Work Program does not currently include any projects to specifically address erosion control along State Road A1A in St. Johns County,” FDOT spokeswoman Sara Pleasants wrote to WJCT in an email.

However, Shinkre said there are several ongoing projects that will help to address A1A’s vulnerability.

“We have several projects that we’re working on, including the Army Corps project to nourish various areas in the county. We also have a state project that we are looking into that would provide nourishment for bringing back the sand that was lost due to Matthew and Irma. We also have a FEMA project that does the same thing,” he said. “So we, as a county, are committed to our citizens and residents to make sure we try to get back the sand that has been eroded in that area.”

And Shinkre said FDOT has always assured the county that if something does happen, the agency will respond immediately to protect the road.

“FDOT monitors the coastline for changes and erosion; problems are addressed when they become a threat to the roadway,” wrote Pleasants.

“The department conducts regular field reviews for erosion on State Road A1A and immediately after any significant storm event,” she explained. “Any erosion found within the department’s right of way is scheduled and repaired as quickly as possible. Solutions vary based on conditions and may be minimal (such as increased monitoring) to major, such as hardening (adding rock revetment and/or sheet pile wall to reduce potential damage from erosion) or relocation (building a new road further from the coastline).”

Meanwhile, in Flagler County, FDOT is beginning the second of a three phase project to repair and strengthen A1A, as reported by the Daytona Beach News-Journal.

Brendan Rivers can be reached at brivers@wjct.org, 904-358-6396 or on Twitter at @BrendanRivers.